1. Field of the Invention
The present invention relates to an ink jet recording apparatus equipped with an ink head that ejects ultraviolet light curable ink and an ultraviolet light irradiation device that moves with the ink head.
2. Discussion of the Related Art
An ink jet recording apparatus that discharges ultraviolet light curable ink from the ink head is known in the art, for example, U.S. Pat. No. 7,232,212. The ink jet recording apparatuses may also be equipped with a device for irradiating ultraviolet light to cure the ink which has been discharged from the ink head on a recording medium. The ultraviolet light irradiation device may irradiate ultraviolet light over the entire region of the recording medium in the left-right direction.
As described in U.S. Pat. No. 7,232,212, an ultraviolet light irradiation device that is attached to an ink head and is carried with the ink head in the left-right direction is also known in the art. The aforementioned ultraviolet light irradiation device is capable of irradiating ultraviolet light on a desired portion of the recording medium, thereby suppressing unnecessary irradiation of ultraviolet light.
It is noted that ink dries upon contact with the air. However, the viscosity of the ink increases when ink within a nozzle dries, and therefore the ejection performance of the ink head may diminish. Also, ink adhered to the nozzle surface may solidify, thereby further diminishing the ejection performance of the ink head. Therefore, an ink jet recording apparatus is provided with a system for maintaining the performance of the ink head, and may also be referred to as an ink head aiding system.
For example, U.S. Pat. No. 7,232,212 describes a capping device equipped with a cap for covering the nozzle surface. The capping device prevents the ink from drying within the nozzle.
In the ink jet recording apparatus with ultraviolet light curable ink which is known in the art, the ultraviolet light irradiation device may light up in unintended moments due to a deficiency in the control program. It is noted that the ultraviolet light irradiation device moves to a position adjacent to or above the ink head aiding system when the ultraviolet light irradiation device moves with the ink head. Therefore, the ultraviolet light irradiation device may irradiate ultraviolet light to the ink head aiding system in an unintended moment. Ink within the ink head aiding system would immediately be cured if ultraviolet light is irradiated on the ink head aiding system. Thus, it would be difficult for the ink head aiding system to perform its original function, and consequently, it becomes difficult to maintain the performance of the ink head.